Ed Sheeran has become one of the world's most bankable musicians and now, the songwriter - who revels in his Irish roots - is set to conquer Croke Park.

Many songwriters talk about being content just to reach a small audience with their music, but from his earliest moments of acclaim, Ed Sheeran had different ambitions. Much like Bono some 30 years before, the carrot-topped troubadour set his sights on becoming one of the biggest acts in the world and he wasn't afraid to shout it from the rooftops.

Many songwriters talk about being content just to reach a small audience with their music, but from his earliest moments of acclaim, Ed Sheeran had different ambitions. Much like Bono some 30 years before, the carrot-topped troubadour set his sights on becoming one of the biggest acts in the world and he wasn't afraid to shout it from the rooftops.

"I'm not ashamed to say I'm hugely ambitious, and I dream of Coldplay-sized fame," he told an interviewer when his major label debut album, +, came out. "Their music has grown to fill the venues they're playing - from rooms to arenas to stadiums, and that's where I want to be one day."

If the words of the then 20-year-old sounded fanciful in 2011, nobody is laughing now. In just four years, the English songwriter, who is said to be immensely proud of his Irish roots, has become globally celebrated and a sell-out attraction in the biggest stadia.

At the weekend he played three shows at Wembley Stadium - an unprecedented achievement for a solo performer - and next weekend he plays to 160,000 people over two nights at Croke Park. And his success is not just confined to these islands - he is arguably the biggest British draw in the US since Adele ripped up the rulebook.

Hot Press deputy editor Stuart Clark says Sheeran has become one of the very few acts capable of commanding such crowds. "His appeal is very wide-ranging," he says. "You've everybody from teens to their parents who like his music and he's managed to retain indie credibility too.

"One of his most striking attributes is his stage presence. While you have bands like Kings of Leon sometimes struggling to work in the 3Arena, he's just this magnetic showman. It helps, of course, by the fact that 14,000 people are singing backing vocals."

Even more impressive, according to Clark, was the one-off concert Sheeran gave in the intimate environs of Whelan's, Dublin, back in January. The venue, which celebrated its 25th anniversary last year, had never seen demand for tickets quite like it. Clark was one of a handful of music critics who got in to see for themselves. "Quite simply, he was mesmerising," he says. "That concert was being filmed [for music channel VH1's Storytellers series] and you had cameras everywhere and that can sometimes suck the life out of a performance, but it had no impact on him whatsoever."

While the past four years have seen Sheeran rise like a comet, it was in the previous four - between the ages of 16 and 20 - and he laid the groundwork. A keen guitarist since 10 or 11, he talks about being enthralled by first Damien Rice [whom he met aged 11 after a gig in the aforementioned Whelan's], and then Christy Moore, and his early songs attempted to capture the searing honesty of both.

There's something charmingly old-fashioned about his attempts to get noticed by issuing a handful of EPs as well as a pair of rough-and-ready homemade albums. He left home at 18 for the bright lights of London's singer-songwriter scene and landed a gig as a guitar technician for Nizlopi, the folksy one-hit wonders behind 'The JCB Song'.

From the start, Sheeran was determined to play as many shows as he could and on reading an interview with the young soulful singer James Morrison, who boasted that he delivered 200 concerts a year, young Ed vowed to beat him. "I played 312 shows in 2009," he said a couple of years later. "Sometimes to no one, or five people, often to more..."

The Stakhanovite work rate paid off as word got out about the earnest young redhead with the killer tunes. Luck played a part too. The actor Jamie Foxx happened upon him in a Los Angeles club and invited him to spend a day recording in his house. Footballer Rio Ferdinand heard one of his songs and tweeted gushingly.

Most influential of all was the interest shown by Elton John, who told journalists that he saw something of his young self in Sheeran's from-the-heart songs. Incidentally, it was Elton John who was Sheeran's special guest during his Wembley performances. (It's been speculated that Bono will surface for the Croke Park shows but Warner Bros label-mate Damien Rice is probably a far safer bet.)

Sheeran's tipping point - the moment he went from hot industry tip to mainstream recognition - happened in the summer of 2011 when he released the gritty, but catchy single 'The A Team'. Inspired by a visit to a homeless shelter, it's about a prostitute addicted to Class A drugs, although it's debatable how many of those seduced by the song paid close attention to the lyrics.

Sheeran is no stranger to Ireland. "We used to go over three or four times a year," he told the Irish Independent in 2011. "We have loads of Irish cousins."

One of them, Galway-native Laura Sheeran, is also a songwriter although her material is decidedly more esoteric than his. They've known each other from childhood and he was among the guests at her wedding to Bell X1 touring member Marc Aubele in Spiddal last summer.

Paul Noonan, frontman of Bell X1, met Sheeran for the first time at the wedding and was struck by how down to earth he was. "Apparently we was a fan of ours," he says. "He said he was at one of our shows in Whelan's and that would have been about 10 years ago. We had a great time, playing songs and jamming together."

Three months ago, Noonan got a call to say that Sheeran wanted Bell X1 to support him at Croke Park. "We were in the middle of making a new album and hadn't really been doing anything on the live front but the prospect of Croke Park was tantalising." (The band played GAA HQ before, supporting U2 when they last played their home town in 2009.)

Sheeran also hand-picked the other support act, Gavin James, a Dublin songwriter tipped by many to 'do a Hozier' with his next album. When I interviewed James a couple of years ago he was enthused to have been among those fledgling acts to receive the Ed Sheeran endorsement. "He's a great songwriter," he told me, "someone who writes songs that stop you in your tracks. He was so generous with his time when I first met him and there were no airs and graces about him whatsoever."

It's a sentiment one hears time and time again. The staff at Whelan's were said to be especially taken with Sheeran's gentlemanly behaviour and a simple perusal of social media will find fans sharing stories about his willingness to engage with them, sign autographs and pose for selfies.

It's also said that although he is a proud Englishman, his Irish background has long been a crucial part of his identity. When his beloved grandfather, Bill, died in 2013, Sheeran played tribute to him at the following year's Grammys by wearing his Gorey Boxing Club tie.

Not many Irish musicians can say they have a sentence as Gaeilge tattooed on their arm, but Sheeran took the plunge last year when he got inked with a translated song line from Northern Irish singer Foy Vance: "Nuair is gá dom fháil bhaile, is tú mo réalt eolais" ("When I need to get home, you're my guiding star").

While one would struggle to find anyone with a bad word to say about Sheeran, he has been the target of derision, most recently from Morrissey. Decrying the lack of "surprise success stories" in music any more, the ex-Smiths man noted: "It's very rare that a record label does something for the good of music. Thus we are force-fed such as Ed Sheeran and Sam Smith, which at least means that things can't possibly get any worse."

As is the wont of celebrities in 2015, Sheeran used Twitter to vent his frustration. "Even you guys [a reference to the NME, which had published the Morrissey story], should think this is absolute b******s. Taking me out of the equation, Sam was the least predictable success story of the last year."

Sheeran and the NME have history. In the wake of +'s release, one of their writers started a popular Twitter hashtag called #howshitisedsheeran? which, the singer subsequently claimed, "became a vehicle for all sorts of crude and personal jibes".

The influential pop critic also had Sheeran in his sights when he hailed him as part of a new beige wave in music he dubbed The New Boring. "It is no wonder the nation's favourite [radio station, BBC Radio 1] was quite so keen to embrace Sheeran," he wrote. "He combines the station's twin obsessions of authenticity (acoustic guitars!) with cool (he sometimes sort of half-raps and collaborates with urban people!)"

Despite his astonishing popularity with the public, Sheeran has not been inundated with glowing reviews from critics and he once quipped that the only publication to give his breakthrough album a good review was the Halifax Courier, a nod to the Yorkshire town near where he spent his early childhood.

But the lack of love he gets from music writers will hardly matter when he takes to the Croke Park stage on Friday night, according to Hot Press's Stuart Clark.

"One of the lovely things about him is that he appears to be really enjoying his success and all the opportunities that it's given him. It can get very boring to hear successful musicians talking about how dreadful it all is.

"I get the impression that he wakes up every day and he has to pinch ­himself that he's living the life he's living.

"I say fair dues to him and I think he'll make a lot of people very happy in Croke Park at the weekend."